Create MultiIndex pandas DataFrame from dictionary with tuple keys

Question

I'd like to efficiently create a pandas DataFrame from a Python collections.Counter dictionary .. but there's an additional requirement.

The Counter dictionary looks like this:

(a, b) : 5
(c, d) : 7
(a, d) : 2

Those dictionary keys are tuples where the first is to become the row, and the second the column of the dataframe.

The resulting DataFrame should look like this:

   b  d
a  5  2
c  0  7

For larger data I don't want to create a dataframe using the growth method df[a][b]= 5 etc as that is incredibly inefficient as it creates a copy of the new dataframe every time such an extension is done (I'm let to believe).

Perhaps the right answer is to go via a numpy array?

Answer 1

Using Series with unstack

pd.Series(d).unstack(fill_value=0)
Out[708]: 
   b  d
a  5  2
c  0  7

Input data

d={('a', 'b') : 5,
('c', 'd') : 7,
('a', 'd') : 2}